Most pleasure boats as well as larger, commercial vessels carry marine fenders on board. These marine fenders are generally cylindrically shaped and are typically put into use when a boat approaches, leaves or is made fast to a dock, piling or bulkhead. When put into use, they are normally dropped over the side of a boat and secured by a line made fast to a cleat on the boat's deck. Most times, the length of the line is adjusted so that the marine fender is vertically disposed alongside the boat's hull or side somewhere between the deck and the water line of the boat. Depending upon the size of the vessel, two or more marine fenders are positioned at spaced intervals along the length of the boat.
The purpose of using marine fenders is to protect the side or hull of the boat by preventing the boat from impacting or scraping against a dock, piling or bulkhead upon its approach or departure. When a boat is made fast to a dock, piling or bulkhead, these marine fenders are kept in place alongside the boat's hull or side to prevent the hull or side from scraping against the dock, piling or bulkhead as the boat rises and falls with flooding and ebbing tides or is pushed toward the dock, piling or bulkhead by the water's current or the wake of passing boats.
In order to be available for use, several marine fenders usually form part of a boat's standing inventory and they must be readied alongside the boat's hull or side in advance of the boat's approach to a dock, piling, or bulkhead. If a boat is crewed only by its captain, readying the marine fenders is an added burden. This burden can become a worrisome task when the single captain must also contend with other moving vessels, or a narrow channel, or brisk winds, or choppy waters, or a combination of all or any of these conditions.